Studying diseases or effects of new drugs on the human body is challenging, not least because of the lack of proper testing models that recapitulate human physiology. Most research is done using... Show moreStudying diseases or effects of new drugs on the human body is challenging, not least because of the lack of proper testing models that recapitulate human physiology. Most research is done using animal models but these often show differences with humans in disease manifestation and responses to drugs. For example, drugs that had no effect on the hearts of animals later turned out to cause lethal arrhythmias in some humans. This – and the ethical issues around animal testing – is why, as in this thesis, there is increasing interest on making human heart models based on pluripotent stem cells (hPSCs). Nowadays small numbers of cells can be collected from a patient (e.g. from blood, urine or skin), reprogrammed to hiPSCs, and then differentiated to heart muscle cells (cardiomyocytes). Since the genetics of the patient are maintained during reprogramming, the phenotype of a genetic disease affecting cardiac function can also be captured. The focus of this thesis has been developing methods to measure these cardiac phenotypes robustly and with sufficient complexity to reflects drug responses and disease of the heart. Our results supported the notion that hPSC models will become human avatars and accurate measurement models able to recapitulate essential human-specific processes. Show less
General aim of this thesis, entitled Guide to the heart, was to explore the generation of multiple human pluripotent stem cell (hPSC)-derived cardiac subtypes and their application for selective... Show moreGeneral aim of this thesis, entitled Guide to the heart, was to explore the generation of multiple human pluripotent stem cell (hPSC)-derived cardiac subtypes and their application for selective pharmacology, understanding human cardiac development and cardiac repair.Approaches for the differentiation of hPSCs to cardiomyocytes (CMs) followed by purification from heterogeneous cultures are described. To generate subtype specific CMs, a protocol for the derivation and characterization of hPSC-derived CMs with atrial identity was developed. HPSC-derived atrial CMs have proven successful as pre-clinical pharmacological tool. The development of a human atrial reporter by CRISPR/Cas9-mediated knockin of red fluorescent mCherry into the genomic locus of atrial-enriched COUP-TFII allowed the selection of atrial and ventricular CMs. In addition, we evaluated the importance of COUP-TFII for atrial differentiation of hPSC and identified that COUP-TFII is dispensable for atrial differentiation of hPSCs. Importantly, hPSC-derived cardiac progenitors (CPCs) alleviated ventricular remodeling and fibrosis after transplantation to the heart in an acute myocardial infarction model in mice. This thesis ends with a review of the native cardiac environment during development, as well as the adult heart in health and disease. This was used to describe current knowledge regarding extracellular matrix preferences for engineering cardiac tissues from hPSC-CMs. Show less
